Greywater recycling devices for flushing toilets are known in the state of the art.
The utility model document ES 1074716U describes a recycling device requiring a double flush tank provided with a greywater inlet and a second network clean water inlet associated with a float configured to regulate a reserve level of said clean water in the tank. Therefore, this recycling device requires a system with two water inlets for flush in the tank of the toilet. However, this represents a great disadvantage for use as the standard toilet tanks only incorporate a single water inlet or opening for flush.
A similar disadvantage would be found in the patent document WO2012118363A1 which describes a compact tank with a greywater reservoir fed from the drain of a sink or shower, and which pumps said greywater into the tank of a toilet. Therefore, the drawback of such systems or devices is that if sufficient greywater for flush is not generated, they cannot flush enough water in the toilet. To obtain a full flush, these types of devices or systems require a second inlet of sanitary or public water in the toilet tank.
Similarly, the recycling device of shower water described in the document ES1075605U only provides a greywater supply. For this purpose, it incorporates a dispenser of disinfectant for greywater and a time programmer for dosing disinfectant in case of long periods of time without a flush.
The document ES1076233U describes a device for recycling greywater in toilets that requires a large number of devices such as a first auxiliary greywater reservoir and a second greywater storage tank, becoming a multi-device system, some of considerable volume, which prevents their use as another modular electrical appliance.
The system or device described in ES2319076B1 patent does not also allow using it as an electrical appliance for consisting of a toilet that, in itself, integrates the collection and storage of greywater from sinks, showers, bidets, to perform its own cleaning of wastewater. This whole process takes place in the main body, which receives greywater from the bathroom electrical appliances through a header pipe which, after filtering, is pumped into two tanks, one being the tank and the other the storage tank, located under the tank, which, together with the collection mechanisms and systems form a main body, which together with the toilet body form a compact unit. As its operation is fully automatic, it allows choosing the water with which to flush the toilet: water from the supply system, greywater, or both at once. But, however, for not being modular, this invention cannot be used in a toilet installed without new works and without replacing elements already present in that toilet.
The heat exchanger and recycling device of greywater which is the object of the ES2344497A1 patent comprises an enclosure fitted with two compartments hermetically isolated from each other and each provided with respective inlets and fluid outlet, the first compartment being intended for storing greywater from a bathtub, shower or the like, and the second for containing the clean water flowing toward a tap or the like (therefore, without outlet of clean water into the tank of a toilet). The device is provided with means for pumping greywater contained in the first compartment, driven by the clean water flowing through the second compartment. Thus, the device comprises a heat exchanger between the greywater stored in the first compartment and the clean water that is introduced into a second compartment through the corresponding fluid inlet. Also an object of this patent ES2344497A1 is a system for the utilization of domestic greywater comprising a device according to the invention, wherein one of the fluid outlets (that of the greywater) of the device is connected to the tank of a toilet.
In general, it is very common that the known recycling devices require the placement of a second system of level sensors inside the toilet tank. To do this, it is known to replace the screws that secure the tank to the toilet by specific screws, of the same diameter as the screws that are being replaced, but with holes through which the water recycled from a wastewater tank circulates and is discharged into the tank. In this way, these known systems, by replacing the supply of sanitary water from the tank, the tank is fed from another point and a different height, requiring the placement of a second level sensor within the tank for recycled water.
Therefore, the devices described have some of the following disadvantages:                High volume and non-modular, complication of installations and underutilization.        They usually have a non-decorative appearance, requiring concealment, normally occupying storage spaces in cabinets not intended or designed for these devices or under the sink.        Difficult in terms of installation and maintenance.        Require the use of pills or liquid disinfectants in the greywater reservoir, and therefore regular maintenance.        Require installing additional equipment or modifications in the toilet tank with consequent inconvenience, need for specialized technicians for the modifications and risks of water leakage during installation, operation, or system maintenance.        